Comparing with where clause using Dictionary

Question

I have a basic dictionary like Dictionary<int,int>, and want to compare it with my dbset on where clause.I tried something as in bellow,but I could not knock it off.I used Tuple<int,int> instead of dictionary,it throws exception "Only primitive types or enumeration types are supported in this context."

public IEnumerable<Tuple<string,string,decimal>> CrossSellingCheck(Dictionary<int,int> idS)

        if (idS.Count == 0) return null;

        var temp = db.CrossSellings   //these lines
          .Where(m => idS.Any(a=> a.Key==m.MainProductId && a.Value==m.MainProductQuantity));  //these lines

          if (temp.Any()) return null;
            return db.Products.Include(i => i.productimagelist)
                .Where(p => temp.Select(m => m.SubProductId).Contains(p.ProductId)).AsEnumerable()
                .Select(item => new Tuple<string, string, decimal>(
                    item.productimagelist.First().ThumbUrl,
                    item.Name,                
                  temp.Single(z => z.SubProductId == item.ProductId).DiscountRate)));